1. Field of the Invention
The invention generally relates to an instantaneous magnetodynamic generator (IMNG) associated with an alternating tunneling current (AC) device. The IMNG can generate, with violent shakes, a large current between arrays of metallic wires (or rods) and a magnetic plate. However, the violent shakes will not damage the arrays of metallic wires or rods during the violent shakes.
2. Description of the Related Art
FIG. 1 shows a conventional DC nanogenerator 8, which includes a top electrode plate 81 and a bottom electrode plate 82. The top electrode plate 81 is a metal plate having a zigzag face coated with platinum (Pt). The bottom electrode plate 82 includes oxide (ZnO) piezoelectric nanowires 821 aligned vertically in an array. The Pt coating on the zigzag face not only enhances the conductivity of the zigzag face, but also creates a Schottky contact at the interface with ZnO. The nanowires 821 are placed at a small distance beneath the zigzag face of the top electrode plate 81. The DC nanogenerator 8 is driven by an ultrasonic wave U to generate a DC current that passes through a load 9. Specifically, the ultrasonic wave U drives the top electrode plate 81 up and down to bend and/or vibrate the nanowires 821 for generation of the DC current.
A side view of the DC nanogenerator 8 is shown in FIG. 2A. When the ultrasonic wave U is not yet applied to drive the top electrode plate 81, the top electrode plate 81 cannot move down to touch the nanowires 821. Thus, no piezoelectric charge can be generated. As shown in FIG. 2B, when the ultrasonic wave U is applied to drive the top electrode plate 81, the top electrode plate 81 can move up and down. As the top electrode plate 81 moves down and presses the nanowires 821, the nanowires 821 are laterally deflected. Since the nanowires 821 are made of a piezoelectric material, their lateral deflections can cause voltage differences between two sides of the nanowires 821, as the negative (V−) and positive (V+) charges shown in FIG. 2B.
Note that when the nanowires 821 are deflected by the top electrode plate 81 too frequently, the nanowires 821 are easily damaged. Therefore, the safety design of the DC nanogenerator 8 needs to be improved.